local n = io.read("*n")
local p = {}
local pinv = {}
for i = 1, n do pinv[i] = 0 end
for i = 1, n do
  p[i] = io.read("*n")
  pinv[p[i]] = i
end
local r = 0
for i = 1, n do
  while i < p[i] do
    local curval = p[i]
    local swapval = curval - 1
    local j = pinv[swapval]
    p[i], p[j] = p[j], p[i]
    pinv[curval] = j
    pinv[swapval] = i
    r = r + 1
  end
end
print(r)